The `platform` field is pointless nesting: it's just stuff that happens
to be defined together, and that should be an implementation detail.
This instead makes `linux-kernel` and `gcc` top level fields in platform
configs. They join `rustc` there [all are optional], which was put there
and not in `platform` in anticipation of a change like this.
`linux-kernel.arch` in particular also becomes `linuxArch`, to match the
other `*Arch`es.
The next step after is this to combine the *specific* machines from
`lib.systems.platforms` with `lib.systems.examples`, keeping just the
"multiplatform" ones for defaulting.
Declaring them as lists enables the concatenation, supporting
lib.mkBefore, lib.mkOrder, etc.
This is useful when you need to extend a service with a pre-start
script that needs to run as root.
Originally, changes to the kernel don't propagate to the other
derivation within the same package set. This commit allows for the
changes in the kernel to be propagated.
A distinct example is setting `boot.kernel.randstructSeed` to a non-zero
length string which would result in building 2 kernels, one with the
correct seed and the other with the zero length seed. Then, when using
an out-of-tree kernel driver, it would be built with the zero length
seed which differs from the non-zero length seed used to boot,
contradicting the purpose of the `boot.kernel.randstructSeed`.
For in NixOS it is beneficial if both plasma5 and pam use the same Qt5
version. Because the plasma5 desktop may use a different version as the
default Qt5 version, we introduce plasma5Packages.
https://github.com/NixOS/nixpkgs/pull/107497 broke booting on many systems that
use tmpOnTmpfs due to the lack of specifying the mount type.
This commit explicitly adds the mount type, which should fix booting
such systems.
The original change may want to be revisited however too.
@poettering decided we only need a limited number of inodes in our /tmp,
so why not limit that for every systemd user? That makes medium-sized nix
builds impossible so this commit restores the old behaviour which is the
kernel default of half the number of physical RAM pages which does not
seem too unreasonable to me.
See https://www.redhat.com/sysadmin/fedora-31-control-group-v2 for
details on why this is desirable, and how it impacts containers.
Users that need to keep using the old cgroup hierarchy can re-enable it
by setting `systemd.unifiedCgroupHierarchy` to `false`.
Well-known candidates not supporting that hierarchy, like docker and
hidepid=… will disable it automatically.
Fixes#73800
